The present invention relates to biosensors that are capable of rapidly quantifying the concentration of biomolecules in a sample solution with high accuracy in a simplified manner, and to methods of producing same.
The detection of a ligand by a receptor (for example, detection of a hormone, an antigen or a pathogenic agent) is important in the diagnosis of diseases and finding of useful biomolecules. Many rapid test methods for detecting ligands with high selectivity and sensitivity have been developed. These include radio-activity-based assays, chemiluminescence assays, magnetic based assays, and fluorescence or colorimetric assays. Immunoassays, such as enzyme-linked immunosorbent assay (ELISA), enzyme immunoassay (EIA), and radioimmunoassay (RIA), are also well known for the detection of ligands such as hormones, antigens or antibodies. The basic principle in many of these assays is that a marker-conjugated (for example, an enzyme-, chromogen-, fluorogen-, or radionucleotide-conjugated) antibody permits antigen detection upon antibody binding. In order for this interaction to be detected as a change in color, fluorescent or radioactive complexes, significant numbers of antibodies must be bound to a correspondingly large number of antigen epitopes. The resulting labeled binding complex often must be isolated from the labeled marker molecules for detection.
Although the prior art methods for measuring biological analytes of interest are useful, many problems arise in the application of these methods in biosensor platforms, such as low sensitivity, selectivity and stability of the sensing device. Moreover, existing methods are often time intensive, tedious and costly. Accordingly, there remains a need for sensitive and robust screening methods for detecting biomolecules in a sample.
Electrochemical biosensors such as an electrochemical peptide-based (E-PB) sensor offer a convenient way to conjugate biosensing elements labelled with a redox molecule on a gold-electrode surface. To date, the most straightforward method to fabricate an E-PB sensor involves direct adsorption of thiolated peptide probes onto the gold electrode surface. Despite being a valuable probe immobilization strategy, conventional methods lacks general surface modification versatility.